Package type sewage ejector



Oct. 27, 1942. c. YEoMANs. ETAL PACKAGE TYPE SEWAGE EJECTOR Filed Aug. 3., 1940 5 Sheets-Sheet 1 ct. 27, 1942. c, YEQMANS :TAL 2,300,039

' PACKAGE TYPE SEWAGE EJECTOR Filed Aug. 5, 1940 5 Sheets-Sheet 2 Oct. 27, 1942. c, YEoMANs ETAL 2,300,039

PACKAGE TYPE SEWAGE EJECTOR Filed Aug. 3. 1940 5 Sheets-Sheet 3 Line Oct. 27, 1942. C. YEOMANS Erl-AL 2,300,039

PACKAGE TYPE sEwAGE EJECIOR I Filed Aug. 3, 1940 5 Sheets-Sheet 4 f-g (s.

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- Oct. 27, 1942. c. Yr-:oMANs Erm. 2,300,039 0 PACKAGE TYPE SEWAGE EJECTOR Filed Aug. 3, 1940 5 Sheets-Sheet 5 Patented Oct. 27, 1942 PACKAGE! TYPE SEWAGE EJECTOR Charles Yeomans, Hubbard Woods, and Harold T. Jeiiery, Chicago, Ill., assignors to Yeomans Brothers Company, Chicago,

of Delaware Ill., a corporation Application August 3, 1940, Serial No. 350,442

6 Claims.

Our invention relates generally to pneumatic sewage ejectors and it has particular relation to certain novel and important improvements therein.

The use of pneumatic sewage ejectors to collect sewage from large-buildings or the like and discharge or eject such sewage into city sewers is well known, and while various types of pneumatic sewage ejectors have been designed and used in the past certain diiliculties or objections are encountered in the use of all of this apparatus. For example, the so-called Shone ejector while a most satisfactory device is quite eX- pensive.' Other less expensive ejectors are not reliable in operation, and none of the prior art devices provide for automatic ventilation of the ejector pit. The principal object of the present invention is to provide an improved pneumatic ejector which can be manufactured at low cost and which will be free from the objections of the prior art devices.`

More kspecifically an important'object of our invention is to provide for improved ventilation of sewage ejector installations and the elimination of the dangerous gases and the objectionable odors sometimes associated therewith. This object is accomplished by providing combination ejector and compressor units which may be completely installed in ejector pits, whereby the compressor units will draw their air supply from within the pits and thereby accomplish automatic or self ventilation of the pits as `an incident to the operation of the apparatus. The unit construction of the apparatus also reduces installation costs and makes possible material reduction in the size of the pit.

In addition to the removal of dangerous gases and objectionable odors, the self-ventilation of the ejector pits accomplishes the very important added function of preventing condensation and sweating therein. Since these ejector pits are ordinarily installed below sub-basement iioors of large buildings or in closed underground chambers in connection with sewage systems, a ccnsiderable amount of condensation and sweating normally takes place therein. Such condensation and sweating causes rusting and corrosion of metal parts of the sewage ejectors in the pits and unless prevented will eventually cause serious damage to the mechanical and electrical apparatus. Heretofore, it has been customary to provide separate Ventilating blower units for the purpose of preventing such condensation and sweating within the ejector pits.

with a suitable fresh air inlet to the pits, the '155.A

(Cl. 10S- 241) amount of self-ventilation incidental to the operation of our ejector units, which are completely housed within the ejector pits, is suiiicient to prevent condensation `and sweating therein, and thus,Y the necessity of providing` separate blowers for ventilation of the pits is eliminated.

This prevention of condensation and sweating is aided by the heat given off within the ejector pits from the compressor units housed therein. A. substantial amount of heat isdissipated and radiated from the air compressor cylinders which, especially in the summer months, tends to equalize the temperature in the pits with that of the external atmosphere lso as to thereby reduce condensation and sweating.

lAs. will hereinafter appear, the combination ejector and compressor of our invention embodies certain other important mechanical features included among which are the use of an off-center common inlet and outlet pipe and an improved control system. The invention also makes possible an improved duplex type unit which is much simpler in construction, much easier to install and service, and much cheaper to manufacture than the known prior art types.

Further objects and advantages of our invention will bevmade more apparent in the accompanying drawings and the following description of certain preferred embodiments thereof.

In the drawings:

Fig. 1V is a sectional view showing a sewage ejector installation forming one embodiment vof our invention;

Fig. 2 is a plan view taken online 2-2 of Fig. 1; Fig. 3 is a View taken on line 3--3 of Fig. 1;

Fig. ,4 is a diagrammatic view of an electrical control system for the sewage ejector installation shown in Figs. 1, 2, and 3;

Fig. 5 is a fragmentary plan View of a duplex sewage ejector forming another embodiment of our invention;

Fig. 6 is anend elevational view taken on line 8 6 of Fig. 5;

Fig..'7 is a diagrammatic view of an electrical circuit .control system for the duplex sewage ejector shown in Figs. 5 and 6;

Fig. 8 shows diagrammatically a control system for a sewage ejector having a standby auxiliary compressor unit;

Fig. 9 shows diagrammatieally a control system for a-sewage ejector including a normal operating compressor, an Iauxiliarystandby compressor, and a high-water alarm which operates in the event of failure of the two compressors; and,

Fig. shows diagrammatically an electrical control system for a two-unit sewage ejector installation wherein it is necessary that the two sewage ejector units shall not empty or discharge at the same time.

Referring now to Figures l, 2, and 3 of the drawings, a combination compressor and sewage ejector unit in accordance with the present invention and the usual associated equipment is indicated in its entirety at I5. The ejector pit is illustrated generally at I6, and the sewage ejector housed therein at I1. The top of the pit I 6 is provided with a man hole cover I8 which may be of any satisfactory type, and an air intake I9.

The sewage supply enters into a man hole pit 23 through a conduit 2l and is conducted from the man hole pit to the sewage ejector I1 through a relatively large sewage inlet pipe 22. A pipe 23 through the wall of the ejector pit I5 connects the discharge side of the ejector I1 with the sewer or other sewage disposal line. The pit I6 and the man hole pit 20 are preferably of masonry construction and are below ground level, as shown. The man hole cover I3 and the cover for the man hole pit 20 are flush or even with the ground or floor level, as shown.

The sewage ejector proper I1 includes a sewage receiver or pot 24 which will ordinarily be of fabricated steel construction. The sewage receiver pot 24 is provided with support legs or members 25 which are anchored to risers 2S in the bottom of the pit I6, as shown.

Sewage is both introduced into and discharged from the sewage receiver 24 through an olf-center elbow pipe fitting 21. The pipe fitting 21 is made up of an inner pipe section 3U, the lower end of which is disposed above the center of the bottom of the sewage receiver 24 while the upper end thereof terminates in one side of the top of the receiver24. A vertical flange section 3| may be welded to the section at its upper end where it ts into the top of the sewage receiver 24. The preformed fitting 21 may be welded into the top of the sewage receiver 24 along the joint 32 in Y order to provide an air-tight connection therewith.

It has been found that by having the inside section 30 of the pipe fitting 21 terminate just above the center of the bottom of the sewage receiver 24, a very desirable result is accomplished. The sewage discharging from the bottom end of the section 30 is directed against the bottom of the receiver 24 and serves to stir up and prevent collection of solid material thereon. This is an important feature in insuring continuous operation of the installation by preventing the plugging or closing of the lower end of the pipe section 3i). That is, this particular arrangement for introducing sewage keeps the solid material therein circulating and swirling through the liquid during the operation of the ejector and insures clearing of the pot 24 of substantially all solids each time it is emptied. In this manner the solids do not remain and decay in the sewage re- Y ceiver 24 and cause the sewage to become septic and in addition cause formation of objectionable and dangerous gases. A septic condition of the ejected sewage would seriously interfere with the subsequent biological purification thereof in the sewage treatment plant.

In order to provide for the connection of the sewage inlet line 22 and the sewage discharge line 23 to the fitting 21, a T fitting 33 is turned on its side and connected to the ange on the fitting 3l, as shown. The side opening in the T fitting 33 is connected to a sewage inlet line 22 through a check Valve 34 and a one-way inlet valve 35. The one-way inlet valve 35 is of the type having a swinging gate 36 which opens on pressure from the inlet side, and which will be forced to its closed position by pressure from its discharge end connected to the side of the T fitting 33.

The top opening in the T tting 33 is connected to the sewage discharge line 23 through a check valve 31 and a one-way outlet valve 40. The outlet valve 43 is of the same type as the inlet valve 35 but is reversely arranged so that its hinged gate 4I will open by pressure from the sewage receiver side, and will be closed by pressure from the sewage discharge line 23.

Having the elbow fitting 21 open in one side of the top of the receiver pot 24 instead of in the center of the top is an important feature. By this particular arrangement the inlet valve 35 and check valve 34 may both bev mounted directly over the top of the receiver 24 instead of to one side thereof, thereby permitting the pit I5 to be several feet smaller in size.

To accomplish the pneumatic ejection of the contents of the sewage receiver 24 when it becomes lled with sewage, a compressor unit indicated generally at 42 is mounted on the top of the receiver 24. The support for the compressor unit 32 comprises a four-legged support frame 43 provided with a fiat base 44 resting on the top thereof. The compressor unit 42 includes an air compressor 45 mounted on the base 44 which is driven by an electric motor 45, likewise mounted on the base 44. The drive shafts of the compressor 45 and motor 45 are coupled at the connection 41 as shown in Figure 2. The air intake side of the compressor 45 is connected to a muiiier and air cleaner 5i) through a short pipe line 5I, while the discharge or high pressure side of the compressor 45 is connected to the sewage receiver 24 through a U-shaped pipe line 52.

A safety valve 53, of the pressure relief type, is provided in the horizontal arm of the U-shaped pipe 52 which will prevent excessive pressure from being built up in the sewage receiver 24. A T fitting 54 is provided in one side of the compressed air line 52, as shown in Figure 1, into which a vent line 55 may be connected. The vent line 55 is provided with a solenoid valve 55 for opening and closing the same. The vent line 55 opens into the man hole 20.

In order to accomplish automatic discharge of the contents from the sewage receiver pot 24 when it becomes filled to the high liquid level, the apparatus includes a motor control system which is responsive to the liquid level in the pot 24. This control system includes a long control electrode 51 which reaches close to the bottom of the receiver 24, and a short control electrode which extends down to the predetermined high-water level.

The short and long control electrodes 51 and 69, respectively, enter through the top of the sewage receiver pot 24 through adapter fitting 6I.

The terminals of the electrodes 51 and 65 may be taken out from the center of a multi-section conduit box 62 mounted on the adapters 6I.

As shown in Figure 4 of the drawings, the control electrodes 5l' and 5D are connected to the terminals of a grounded control relay 53 which is connected to an electrically operated solenoid valve 56 in the vent line 55. The relay 53 is connected in circuit relationship to an .electrically operated motor starter 65. The relay 53, the

solenoid valve 58,-and the starter 65 may be of any suitable standard type. 'Ihe terminals' of themotor 46 are connected to three terminals of the starter 65 through three conductors as shown. Power is supplied to a supply line '66 through suitable conductors. Y

The control equipment is preferably enclosed in a suitable box 61 mounted on one side of the support frame 43, as shown in Figures 2 and 3, or it may be mounted on the wall of the pit.

InV operation the solenoid valve 56 is normally energized and open, thereby venting the sewage receiver pot 24 and allowing it to fill up with sewage from the sewage supply line 22. It will be understood that a solenoid valve maybe used which is normally de-energized Yand opened, and which closes on being energized. When the sewage level reaches the lower end of the short electrode 60, an electrical circuit will be established between the electrodes 51 and 60 which' serves to trip the relay 63. This tripping of the relay 63 in turn de-energizes the solenoid valve 56 so as to close the same, and energizes the starter 65, thereby effecting the starting of the compressor motor 46 which drives the compressor 45. The vent line 55 being closed, the compressor 45 will build up pressure within the top of the sewage receiver 24 suiciently to blow the contents out through the pipe section 3U and up through the T fitting 33, one-way outlet valve 40, check valve 31, discharge line 23, and into the sewer or other disposal line.

As the sewage is discharged from the receiver 24 the circuit between the electrodes 51 and 60 will be broken thereby resetting the relay 63. This resetting of the relay 63 cuts out the starter 65 and de-energizes the motor 46, thereby stopping the compressor 45. rZit the same time, the solenoid valve 56 is energized and opens, thereby opening the vent line 55 and allowing the pressure within the receiver 24 to be released.

Having `the sewage ejector I1A housed as a unit within the pit I6 is a very important feature of theinvention for the reason that it accomplishes automatic ventilation of the pit wherein the sewage ejector is installed.r Heretofore, in sewage ejector installations the air compressor units have been positioned outside of the pits in which' the sewage ejectors were housed. In spite of the fact that the sewage receivers were hermetically sealed, and the piping joints carefully tightened, `it was impractical to` prevent a certain amount of sewer gas from escaping into the pits. Such sewer. gas feeping or leaking into the building wherein the ejectors are installed is both dangerous and obnoxious. In addition, as stated above, it has heretofore been necessary to provide separate blower units to ventilate ejector pits and prevent objectionable condensation and sweating therein. Inv the present invention the air supply for the compressor 45 is drawn in directly from the pit I6 through the. air cleaner and muiiler 50, while the sewage receiver 24 is vented through the pipe line 55 opening outside the pit I6. This intake of pit air through the muiiler l) and discharge without thepit I6 serves to ventilate the same. Condensation and sweating is thus prevented, and dangerous gases and objectionable odors -removed as an incident to the operation of our improved sewage ejector installations and the requirement of separate Ventilating apparatus is eliminated. rBesides this important ventilation feature,

having the sewage ejector I1 housed as a unit in the pit I6 reduces the installation space from yage receiver bodies,

rfittings 92 welded thereto.

that normally required heretoforev where'the compressor units were not mounted on the sew- In certain vinstances it isY desirable to couple two sewage ejectors in one installation. x This may be desirable where,ralthough ordinarily one sewage ejector provides suflicient sewage ejection capacity, there may be certain peak or overload periods in which additional capacity is required. Furthermore, in such a duplex unit, one of th'e sewage ejectors may serve as an auxiliary or standby ejector in case of breakage or failure of the other, l

In Figures' and 6 of the drawings a duplex or double sewage ejector unit is designated generally at 10 incorporating the novel features of the single sewage ejector unit I1 shown in Figures 1, 2, 3, and 4 of the drawings. The sewage ejector 10 is housed within a masonry pit1I and includes a barrel-shaped tank body 12 carried by legs 13 secured on a riser 14 in the floor of the pit 1I as shown. y

The 'tank 12 is divided into two separate sewage receiver compartments A and B by a header partition 15 welded within the tank 12. Each of the compartments A and B is provided with' a 'super-structure arrangement, similar to the super-structure of the sewage ejector I1 of Figures 1, 2, and 3, including a compressor unit 16, sewage inlet. line 11, sewage discharge line and suitable valves. In fact, superstructure units substantially identical with the superstructure unit used on the sewage ejector I1 may be mounted on each of the compartments A and B. Certain minor modifications such as the lengths of the electrodes, and the pipe discharging the sewage into the compartments A and B may be necessary` The -sewage inlet line to each of the compartments A and B includes a ch'eck valve 8| and a one-way inlet valve 82, while each of the dischargelines B0 includes a check valve 83 and a one-way outlet valve 84. The sewage inlet line 11 leads from the sewage source into the pit 1I. Two T ttings 86 and 81 are provided in the sewage supply line 11 having the side openings thereof connected with the inlet side of each of the check valves 8|.

Sewage is both introduced into and discharged from the compartments A and B through pipe nti-ings 90 as shownin Figure 6. The ttings 90 are angle-shaped and include pipe Sections 9| terminating close to the center of the bottom of each` ofthe compartments A and B, withupper The fittings 82 t in holes in the top of the tank 12 and are welded therearound both for support and to provide an air-tight seal. The same cleaning and swirling action is obtained when sewage is discharged from the lower ends of the pipe sections 9| into the compartments A and B as described heretofore in connection with introduction lof sewage into the receiver 24 of the sewage ejector I 1. Each ofthe compartments A and B is provided with a long electrode 93 reaching close to the bottom. of the compartments, and a short electrode 94 reaching to the highwater level. The mounting structure for these electrodes 93 and 94 is similar to that for the electrodes 51 and 6I! of the sewage ejector I1 and will not be described in detail.

InFig-ure 7 of the drawings the electrical control system for the sewage ejector 10 is shown.

Essentially, this electrical control system comprises the combination of two control systems siinilar to' the one for the sewage ejector I1 shown'in Figure 4 of the drawings. That is, a control system is provided for each compartment A and B whichmay be 'substantially a duplicate of the control system Vof Figure 4. It will be seen that only one currentV source is required. The vent lines for. the 'compartments A and B, the solenoid valves, thel relays, motor starters, and current source, have been given prime reference numerals to correspond with like elements in Figure 4. A" detailed description of. this electrical controlsystem is not necessary.

In the operation of the sewage ejectors 13, the sewage normally ilows through the inlet line 11 and into the sewage compartment A. When this compartment A is filled to the high liquid` level, an electric circuit will be completed between the two electrodes 93 and 34 therein, and the contents will be discharged by the compressor unit 16 ina manner analogous to that described in connection with sewage ejection from the sewage ejector I1. After the discharge of the compartment A the air vent line 55 therefor will be opened bythe energization of the solenoid valve 53 therein, and the compressor unit 'I6 will be shut down. It will be seen that the cycle of operation is theA same as that of the cycle of operation of the sewage ejector I1 in Figures 1, 2, 3,

and'4. v Any sewage flowing through the sewage supply line 'I1 while sewage is being ejected from compartment A will ow into the compartment B until the compartment A is vented. When the compartment B becomes filled to its high water level, the sewage will be likewise discharged therefrom in Y the same manner as sewage is ejected from the compartment A.

In one installation it was found that the compartment B became iilled with sewage about once while the compartment A was filled and discharged 6 times. This ratio will vary depending upon the installation. However, it will be seen'that in case a great deal of sewage is being emptied through the sewage inlet line I'II the compartment B will be lled more often.

The sewage ejector unit 1I) has the same advantages in respect-to pit ventilation and compactness as the sewage ejector I1 described in connection with Figures l, 2 and 3. In addition it is much more compact than duplex units control system for such an installation is shown inFigure 8 of the drawings. A sewage receiver I Ill is provided with a long electrode I I reaching close to the bottom of the receiver IIU and a short electrode |I2 reaching to the normal high water operating level. The electrodes I II and I I2, together with a ground I I3, are connected to a relay I I4 through suitable conductors. The relay ||4 is also connected in circuit relationship with a solenoid valve ||5 of a vent line IIB for the sewage receiver IIB, and with an electrically operated motor starter IIT serving to control a driving motor II@ for the compressor unit |20.

The motor starterl I I1 is electrically connected through suitable conductors to a power source I2 I, which may be a three-wire, 220 volt, 60 cycle line. When the sewage reaches the normal high water level and covers the end of the short electrode IIZ, an electrical circuit will be completed between the electrodes III and I I2 thereby causing the operation of the relay II4. This serves to close the solenoid valve I5 and start the compressor unit |20. When the contents of the receiver III) have been emptied, the relay I|4 will be reset thereby de-energizing the motorof the compressor unit |20 and energizing and opening the solenoid valve I I5.

In order to insure positive ejection of the contents of the sewage receiver I I, a standby compressor unit |22 is provided. A relatively short electrode |23 is provided in the top of the sewage receiver, which does not reach to the normal predetermined high water level. A relay |24 is provided which is connected in circuit relationship with the ground II3, the long electrode III, and the short electrode |23, as shown. The relay |24 is also connected in circuit relationship with a motor starter |25 serving to control a driving motor I8 for the compressor unit |22. The motor starter |25 is also connected to the current source of line I2 I. Y

In the event of failure of the compressor unit |20 to operate, the sewage will continue to rise in the receiver III] until the end of the short electrode |23 is covered. On this occurrence, an electrical circuit is established between the electrode |23 and the long electrode III which acts to operate the relay |24. This operation of the relay |24 cuts in the motor starter |25 and starts out with the auxiliary compressor unit |22. This unit will then serve to discharge the contents from the sewage receiver III).

Referring to Figure 9, a pneumatic sewage ejector control system is shown incorporating a high water alarm or safety device in combination with an auxiliary type air compressor arrangement. The liquid level responsive system includes a long control electrode |23 reaching adjacent to the bottom of sewage receiver |21, and a short control electrode |30 which reaches to the normal high water level to which the sewage rises in the receiver |21, The short control electrode |30 is adapted to control the normally operating compressor unit indicated generally, at |3| of the storage ejector installation.

A second short control electrode |32 is provided in the top of the receiver |21 which reaches to a depth somewhat above that to which the electrode |30 reaches, and a third short electrode |33 is provided in the top of the receiver |21 which reaches to a depth some what above that to which the short electrode |32 reaches. The electrode |32 is adapted to control a standby compressor unit, indicated generally, at |34, and the short electrode |33 is adapted to control a high water alarm |35, as will appear hereinafter.

The long control electrode |23, the electrode |30, and a ground |36 are connected in circuit relationship with a grounded relay I 31 through suitable conductors, as shown. The terminals of a solenoid valve |43 which controls the vent line IIII for the sewage ejector |21 are also connected to the relay |31. The relay |31 is further connected in circuit relationship with a motor starter |42 which serves to start the motor of the compressor unit |3| and is electrically connected therewith. In order to energize this part of the system, the motor starter |42 is connected in circuit relationship with a suitable power source, such as the line |43. The line I 43 may be the ordinary three-wire, 220 volt, 60 cycle current source.

In order to control the standby or auxiliary compressor unit |34, the long electrode |26, the short electrode |32, and the ground |36 are connected to a second grounded relay |44, which is also connected in circuit relationship with a motor starter |45, which serves to start the motor of the compressor unit I 34. For energization, the motor starter |45 is connected to the powerline |43.

The short electrode |33, the long electrodeV |26 and the ground |36 are electrically connected to a third grounded relay |46. The relay |46 is connected with an alarm bell |35 and also with the current source |43, as shown. It will be understood that other forms o f high water alarm, such as a light, may be used instead ofthe bell |35.

In operation, the sewagereceiver |21 normally lls to the lower end of the short electrode |30, whereupon an electric circuit is established between the electrode |30 and the long electrode |26 which serves to effect the operation of the relay |31. On operation of the relay |31 the compressor unit 3| is started and the solenoid valve |40 closes, thereby ejecting the contents of the sewage receiver |21. In caseY thecompressor unit, 3| fails to operate, the sewage will continue to rise until it covers the end of the short electrode |32, whereupon the relay |44 will be operated, starting up the compressor unit |34, and discharging the sewage from the receiver |21. In the event that neither of the compressor units |3| or |34 operates in the usual manner, the sewage will rise above the electrode |33 thereby operating the relay |46 and setting off the alarm |35.

There are certain instances in the case of duplex sewage ejector installations in which it is necessary to insure that the two separate sewage receivers are not discharged at the same time. One example of such an instance occurs where both of the sewage receivers discharge into a common sewage discharge line which is abnormally small in cross sectional area or of very long length, The capacity of such a discharge line being relatively small, an abnormally high pressure will be required to` overcome the pipe friction and discharge the contents of the twov sewage receivers simultaneously therethrough. In Figure 10 of the drawings, an electric control system for a duplex sewage ejector installation is shown wherein the simultaneous discharge of two sewage receivers |41 and |50 is prevented.

The sewage receiver |41 is provided with long and short electrodes and |52, respectively, which, together with a ground |53, are connected to the terminals of a relay |54. `The relay |54 is connected with a solenoid valve |55 which controls the vent line |56 forthe sewage receiver 41. In order to pneumatically discharge the contents of the receiver |41, a compressor unit indicated generally at 51 is provided, the electric driving motor |58 of which is adapted to be started by a motor starter |60 electrically connected therewith. The motor starter |60 is also connected in circuit relationship with the relay |54 andv to a current source |6|.

The sewage receiver |50 is likewise provided with long and short electrodes |62 and |63, respectively, whichtogether with the ground |53 are connected to the terminals of a second relay 64. Two terminals of the relay |64 are also connectedto a solenoid valve 65 serving to open'and close a vent line |66 for the sewage receiver |50. The sewage receiver |50 is discharged bya compressor unit indicated generally at |61 driven by an electric motor |68. `.The electric 'motor |68of the compressor unit |61 is connected with a motor starter which may be of the same type as the motor starter |60. The motor starter |10 is connected in circuit relationship with the relay |64,

and to the power source |6| for energization.

In order to prevent dual or simultaneous operation of the two sewage ejectors,l each of the motor starters |60 and |10 is provided With a solenoid switch indicated generally at |1| and |12, respectively. The solenoid switch |1| Aincludes a coil 13,- an armature.|14, and a contact member |15. The contact member |15 depends from the bottom of the armature |14 and is insulated therefrom. When the solenoid or coil |13'is de-energized, and the armature |14 is in its lower position, the contact member |15 rests on two contact points |16A and completes a circuitl therebetween, as will appear hereinafter. Likewise, the solenoidfswitch |12 includes a solenoid or coil `|11 and an armature |80 from which acontact member I 8| is supported in' insulated relationship. When the solenoid |11 is deenergized, and the armature is in its lower position, the contact member 8| completes a circuit between twocontact points |82.

As shown in the drawings, both of the contact members |15 and |8| are resting on the contact points 16 and |82, respectively. The broken line outlines of the contact members |16 and |8| indicate their upper positions which they take when the solenoids |13 and |11, respectively, are energized. Y

One of the terminals of each of the solenoids |13 and |11` isconnected to a terminal of a re,- versing switch unit |83. The second terminal of the solenoid |13 is connected'to one ofthe contact points |82 of the solenoid switch |12,while the second terminal of the solenoid |11 is similarly connected to one of thecontactpoints 16 of-the solenoid switch |1|. Each of the other contact points |16 and |82 is connected to opposite terminals on the "reversible switch unit |83, as shown. In order toenergize the alternator switch unit |82 it is connected by two'conductors to the line- |6|. Y

When the sewage receiver^|41 iills upand a circuit is established between the electrodes |5| and |52, the relay .|54 is in turn operated, starting Vup the compressor unit 51 in the usual manner. 'I'his operation or trippingy of the relay |54 also serves to operate the reversible switch unitv 83 and energize the solenoid switch 12 in the motor starter 10, thereby lifting the contact member 8| from the contact point |82 and preventing the motor starter I 10 from starting the motor of the compressor unit |61. The solenoid switch |1| in the motor starter |60 remains de-energized and closed, permitting the motor ofthe compresosr unit |51 to be started. Conversely, when the sewage receiver|50 lls and the relay |64 trips, the reversible switch u nit |83 will reverse and the solenoid switch. |1| will be energized thereby lifting the contact member |15 from the contact points |16 and preventing the compressorunit |51 fromstarting, while the switch |12 isv deenergized and closed allowing the moto-r starter |10 to start the compressor unit |61.

Accordingly, it will be seenvthat when either of the sewage ejectors |41 or v |50 lls up, the control system prevents the other sewage ejector from discharging until the first has been emptied. In this way simultaneous discharge of sewage from the two sewage ejectors |41 and |50 of the installation is prevented. V

.Since certain further changes may be made in the foregoing constructions yand arrangements,v

and different embodimentsof our invention may be made Without departingfrom the scope thereofi, it is intended that all matter described hereinbefore or shown in the accompanying drawings shall be interpreted as illustrative and not in a limited sense, and that the accompanying claims shall be" accorded the broadest construction consistent with the prior art.

We claim the following as our invention:

1. A sewage ejector vinstallation comprising, in combination; a closed pit; an air inlet into said pit; and a pneumatic sewage ejector completely housed in said pit and comprising an air-tight sewage receiver, a sewage inlet conduit connecting said sewage receiver with the sewage supply outside of said pit, a one-way inlet valve in said sewage inletl conduit, a sewage ejection conduit connected to said sewage receiver and terminating outsideof' said pit, a one-way outlet valve in .said sewage ejection conduit, an air compresso-r adapted to draw air into said pit through said air inlet therein and connected to said sewage receiver for delivering compressed air thereinto, driving means for said air compressor connected in driving relationshiptherewith,I an air intake in said pit for said air compressor, air vent means connected with said sewage receiver and opening outside oi said pit, valve means for said air vent means, and control means responsive to the liquid level of the sewage in said sewage receiver for controlling said air compressor and said air vent valve means.

2. A pneumatic sewage ejector comprising, in combination, an air-tight sewage receiver, pipe means having one end opening inside of said sewage receiver adjacent to the bottom thereof, a sewage inlet pipe connected with said pipe means, a one-way inlet valve in said sewage inlet pipe, a sewage discharge pipe connected with said pipe means, a one-way outlet valve in said sewage discharge pipe, a compressed air source connected to said sewage receiver, 'an air vent for said sewage receiver; a valve for opening and closing said air vent, and control means responsive to the liquid level of the sewage in said receiver for controlling the admission of cornpressed air from said compressed air source and for controlling said air vent valve, sewage being fed into said sewage receiver through said pipe means when the receiver is vented through said air vent and said compressed air sourceis shut off, and sewage being ejected from the sewage receiver through said pipe means, when said air Vent is closed, by compressed air from said compressed air source which is turned on.

3. A pneumatic sewage ejector comprising, in combination, an air-tight sewage receiver, pipe means having one end opening inside of saidsewage receiver near the center of the bottom thereof and the other end opening outside of said sewage receiver at one side thereof, a three-opening tting with one of its three openings connected with the outside opening of said pipe means, a sewage inlet pipe connected with another one of the three openings of said fitting, a one-way inlet valve in said sewage inlet pipe, a sewagedischarge pipe connected with the remaining opening of said fitting, a one-way outlet valve in said sewage discharge pipe, acompressed air source connected to said sewage receiver, an air vent for said sewage receiver, a valve for opening and closing said air vent, and control means responsive to the liquid level of the sewage in said receiver for controlling the admission of compressed air from said compressed air source and for controlling said air vent valve, sewage being fedinto said sewage receiver through said pipe CTI.

means when the receiver is vented through said air vent and when said compressed air source is shut off, and sewage being ejected from the sewage receiver through said pipe means by compressed air from said compressed air source when said air vent is closed.

4. A pneumatic sewage ejector comprising, in combination, an air-tight sewage receiver, pipe means having one end opening inside of said sewage receiver at a point near the center of the bottom thereof and having the other end opening through one side of the top of said sewage receiver, a sewage inlet pipe connected with the top end of said pipe means, a one-way inlet valve in said sewage inlet pipe, a sewage discharge pipe connected with the top end of said pipe means, a one-way outlet valve in said sewage ejection pipe, an air vent pipe connected with said sewage receiver, a solenoid valve in said air vent pipe for opening and closing the same, a support base mounted on the top of said sewage receiver, an air compressor mounted on said support base, an electric motor mounted on said support base and connected in driving relationship with said compressor, a compressed air pipe connecting said air compressor with said sewage receiver, an electrical current source, electrical control means responsive to the liquid level of the sewage in said sewage receiver connected in circuit relationship with said current source, and conductor means connecting said solenoid valve and said electric motor in circuit relationship withrsaid control means whereby when the level of the sewage in the sewage receiver is below a predetermined high level the solenoid Valve is open and the electric compressor motor is deenergized permitting said sewage receiver to fill with sewage, and whereby when the level of the sewage reaches said predetermined high level said solenoid valve is closed and said electric compressor motor is energized and drives said air compressor, the pressure built up by said air compressor serving to eject the contents of said sewage receiver through said pipe means and said sewage discharge pipe.

5. A sewage ejector installation comprising, in combination, a closed pit; an air inlet into said pit; and a pneumatic sewage ejector completely housed in said pit and comprising, an air-tight sewage receiver, pipe means having one end opening inside of said sewage receiver at a point near the center of the bottom thereof and having the other end opening through the top of said sewage receiver, a sewage inlet pipe connected at one end to arsewage supply outside of said pit and connected at the other end to the top of said pipe means, a one-way inlet valve in said sewage inlet pipe, a sewage discharge pipe connected at one end to the top endof said pipe means and terminating at its other end outside of said pit, a one-way outlet valve in said sewage discharge pipe, an air vent pipe connected at one end to said Sewage receiver and opening outside of saidv pit at the other end, a solenoid valve in said air vent-pipe for opening and closing the same, a support base mounted on the top of said sewage receiver, an air compressor mounted on said support'base, an electric motor mounted on said support base and connected in driving relationship with said compressor, an air intake in said pit for said air compressor, a compressed air pipe connecting said air compressor with sewage receiver, `an electrical current source, electrical control means responsive to the liquid.V level of the sewage `in saidv sewage receiver connected in circuitrelation'ship with said current source, and

conductor means connecting said solenoid valve and said electric motor in circuit relationship with said control means whereby when the level of the sewage in the sewage receiver is below a predetermined high level the solenoid valve is open and the electric compressor motor is deenergized permitting said sewage receiver to fill with sewage, and whereby when the level of the sewage reaches said predetermined high level sai-d solenoid valve is closed and said electric compressor .motor is energized and drives said air compressor, the pressure built up by said air compressor serving to eject the contents of said sewage receiver through said pipe means and said sewage discharge pipe.

6. A pneumatic sewage ejector comprising, in combination, an air-tight sewage receiver; a partition dividing said sewage receiver into two separate sewage compartments; rst pipe means having one end opening inside of one of said sewage compartments near the centerA of the bottom thereof and having the other end opening through the top of said one sewage compartment; second pipe means having one end opening inside the other of said sewage compartments near the center of the bottom thereof and having the other end opening through the top of said other sewage compartment; a sewage supply line; a pair of sewage inlet pipes connecting the top ends of said rst and second pipe means with said sewage supply line; a one-way inlet valve in each of said pair of sewage inlet pipes; a pair of sewage discharge pipes connected with the top ends of said first and second pipe means; a one-way outlet valve in each of said pair of sewage discharge pipes; an air vent pipe connected to each of said sewage compartments; a solenoid valve in each of said air vent pipes for opening and closing the same; a rst support base mounted on the top of one of said sewage compartments; a second support base mounted on the top of .the other of said sewage compartments; a hrst air compressor mounted on said irst support base; a rst electric moto-r mounted on said first support base and connected in driving relationship with said irst compressor; a second air compressor mounted on said second support base; va second electric motor mounted on said second support base and connected in driving relationship with said second compressor; a pair of compressed air pipes for connecting each of said air compressors with one of said sewage compartments; an electrical current source; electrical control means for each of said sewage compartments responsive to the liquid levels of the sewage therein and connected in circuit relationship with said current source; and conductor means connecting each of said solenoids and each of said electric compressor motors in circuit relationship with said control means; whereby when the sewage in either of said compartments reaches the predetermined high liquid level the electrical control means associated therewith closes the air vent valve associated therewith and starts the compressor motor of the air compressor associated therewith, thereby ejecting the sewage from that compartment.

CHARLES YEOMANS. HAROLD T. JEFFERY. 

